GA/T 842-2019Examination methods for ethanol concentration in blood (English PDF)

7.1 Qualitative analysis

7.1.1 Sample preparation

7.1.1.1 Case sample preparation

Take 0.10 mL of whole blood to be tested and 0.50 mL of tert-butanol internal standard working solution into a sample bottle, cover with a silicone rubber pad, and seal aluminum with sealing forceps.

Cap, mix well, to be tested.

7.1.1.2 Preparation of blank samples and added samples

Take 1 mg/100 mL ethanol standard working solution 0.10 mL and tert-butanol internal standard working solution 0.50 mL into the sample bottle as the detection limit Add samples, and take another 0.10 mL of blank whole blood and 0.50 mL of tert-butanol internal standard working solution into the sample bottle as a blank sample. As per 7.1.1.1 Method operation, parallel control analysis with case samples.

7.1.2 Detection

7.1.2.1 Reference conditions for gas chromatography detection

The reference conditions for gas chromatography detection are shown in Table 1. It can be adjusted according to the actual situation of different brands of instruments and different samples.

Table 1 Reference conditions for gas chromatography detection

reference

condition

Column 1)

Column temperature

Carrier gas flow rate mL/min Detector Detector temperature Inlet temperature DB-ALC1 (30 m × 0.32 mm × 1.8 µm) hair Thin column or equivalent column Flame off Sub-test Tester (FID) 250.200 DB-ALC2 (30 m × 0.32 mm × 1.2µm) hair Thin column or equivalent column PLOT-Q (30 m × 0.53 mm × 20.00 µm) hair Thin column or equivalent column 5 rbowax 20 M/Carbopack (80 ~ 120 Mesh) 2 m × 2 mm packed column or equivalent column 70 20 ~ 40

7.1.2.2 Reference Conditions for Headspace Sample Analysis Reference Conditions for Headspace Autosampler

a) Heating box temperature. 65 °C;

1) DB-ALC1 and DB-ALC2 are suitable examples of commercially available products. This information is given for the convenience of the users of this standard and does not imply that Approved.

b) Loop temperature. 105 °C;

c) Transmission line temperature. 110 °C;

d) Heating equilibration time of sample bottle. 10.00 min;

e) Sample bottle pressurization time. 0.10 min;

f) Filling time of the loop. 0.10 min;

g) Loop equilibrium time. 0.05 min;

h) Injection time. 1.00 min.

7.1.2.3 Injection

Place the prepared sample on the headspace autosampler sample rack, prepare an injection method, and run it.

7.1.3 Records and calculations

Record the retention times of t-butanol, ethanol standards, and suspicious ethanol peaks in each sample, and calculate the ethanol relative to t-butanol in each sample Relative retention time value.

7.2 Quantitative analysis

7.2.1 Sample preparation

7.2.1.1 Case sample preparation

Take 0.10 mL of the whole blood to be tested and add 0.50 mL of tert-butanol internal standard working solution, the sample preparation is the same as 7.1.1.1.

7.2.1.2 Preparation of calibration curve

Configure a series of standard ethanol working solutions. Take a series of 0.10 mL of each standard working solution and t-butanol internal standard working solution 0.50 mL was added to each sample vial. The sample preparation was the same as 7.1.1.1.

The concentration of the ethanol standard working solution series used to prepare the calibration curve should be no less than six step concentrations, and the ethanol concentration of the sample to be measured should be in the school Within the linear range of the quasi-curve.

7.2.2 Detection and recording

According to 7.1.2, record the peak area values of ethanol and t-butanol in the case samples and the series of standard working solution samples.

7.2.3 Calculation

7.2.3.1 Calibration curve

Linear regression of the mass concentration of ethanol using the ratio of the peak area of ethanol to t-butanol in a series of standard working solution samples yields the line Sexual equation.

7.2.3.2 Quantitative

According to the peak area values of ethanol and internal standard tert-butanol in the case sample, calculate the ethanol content X in the case sample according to formula (1).

In the formula.

X--Ethanol content in the case sample, in milligrams per 100 milliliters (mg/100 mL);

Y--peak area ratio of ethanol and internal standard tert-butanol in the case sample;

a--intercept of linear equation;

b--the slope of the linear equation.

7.2.3.3 Calculate Relative Phase Difference

The relative difference between the ethanol content of the two case samples in parallel operation is calculated according to formula (2).

RD (%) = 0

XX 21

In the formula.

RD-relative phase difference;

X1, X2--the quantitative determination of ethanol content in two cases;

X-Mean value of ethanol content of two case samples measured in parallel.

8.1 Evaluation of Qualitative Results

8.1.1 Positive results

It is normal that no chromatographic peak of ethanol appears in the blank sample, and that of both ethanol and t-butanol in the added sample is normal. blank and the addition sample is normal, the relative retention time (or retention time) of the chromatographic peak in the case sample and the relative retention time of the ethanol in the addition sample (Or retention time) comparison, the relative error is within ± 2%. After testing with different chromatographic conditions, if the results are consistent, it is determined that the Contains ethanol.

8.1.2 Negative results

The blank and added samples are normal, the t-butanol peak of the case sample is normal, and when there is no peak of ethanol, the test result is considered negative.

Sex. If the result of the blank and/or added sample is abnormal, it indicates that the operation is wrong and the result is invalid. It should be re-examined.

8.1.3 Detection limit

The detection limit of ethanol in blood by this method was 1 mg/100 mL.

8.2 Evaluation of quantitative results

8.2.1 Calibration curve

The linear correlation coefficient r of the ethanol content calibration curve is not less than 0.999, and the calibration curve is valid.

8.2.2 Quantitative results

When the relative difference between the measurement results of two case samples measured in parallel is not more than 10% (the blood sample with clot should not exceed 15%), the quantitative results are valid, and the quantitative results are calculated based on the average of the measurement results of the two case samples, otherwise the measurement needs to be repeated.

8.2.3 Limit of quantitation

The limit of quantification of ethanol in blood by this method was 5 mg/100 mL. The qualitative analysis results of the case samples were positive, and the quantitative analysis of ethanol content when the amount is less than 5 mg/100 mL, the test result is that ethanol is detected in the blood, and the content is less than 5 mg/100 mL.